Abdominal exercise machine



FIG. 1. is a perspective view of our abdominal exercise machine;

FIG. 2. is a front view thereof;

FIG. 3. is a back view thereof;

FIG. 4. is a left side view thereof;

FIG. 5. is a right side view thereof;

FIG. 6. is a top view thereof; and,

FIG. 7. is a bottom view thereof. 

The ornamental design for an abdominal exercise machine, as shown and described herein. 